Thank you, Martin. I'm definitely learning to be more cautious with those Ancestry trees.
Old Ohio Home- that's the route I took to find the names Peter & Jane

Sorry, it was all a bit complicated to explain.
DaisyPetal - Jane Underhill is where I landed at first, too!

Which is why I was trying to understand the Jane Honora Dwyer name that popped up so many times because I thought I'd really gone wrong and missed something obvious. It's really thrown me but maybe Honora Dwyer's just an Ancestry red herring? Very good point too about the earlier birth date for susan. It's strange that she's the only one not baptised out of what looks like a huge family. I'll keep looking.
Fiddler'sLass - very good question! I haven't gone back on Peter's line yet as was so focussed on unpicking Jane's side, but wondered if he was Peter's brother.